The art of mountaineering is half physical and half mental. He who can justly claim the name of mountaineer must possess the power to _lead_ up rocks and snow, and to cut steps in ice. This is the physical side of the business. It is important; but the charm of mountaineering is largely intellectual. The mental equipment of the mountaineer involves an exhaustive knowledge of one of the most ruthless aspects of Nature. The mountaineer must know the hills in all their changing moods and tenses. He must possess the power to make instant use of trivial clues, a power which the uninitiated mistake for an instinctive sense of direction. Such a sense is undoubtedly possessed by a small minority, but path-finding is often usually only the subconscious analysis of small clues. The mountaineer must understand the secrets of snow, rock, and ice. He must be able to tell at a glance whether a snow slope is dangerous, or a snow-bridge likely to collapse. He must be able to move with certainty and safety on a rock face, whether it is composed of reliable, or brittle and dangerous rock. All this involves knowledge which is born of experience and the power to apply experience. Every new peak is a problem for the intellect. Mountaineering, however, differs radically in one respect from many other sports. Most men can get up a mountain somehow, and thereby share at least one experience of the expert. Of every hundred boys that are dragooned into compulsory cricket at school, only ten could ever by any possible chance qualify to play in first-class cricket. Almost all of them could reach the summit of a first class peak if properly guided. But this is not mountaineering. You cannot pay a professional to take your place at Lords’ and then claim the benefit of the century he knocks up. But some men with great Alpine reputations owe everything to the professional they have hired. They have good wind and strong legs. With a stout rope above, they could follow a good leader up any peak in the Alps. The guide was not only paid to lead up the rocks and assist them from above. He was paid to do all the thinking that was necessary. He was the brain as well as the muscle of the expedition. He solved all the problems that Nature sets the climber, and mountaineering for his client was only a very safe form of exercise in agreeable surroundings.